Field of invention
This invention is related to hydraulic fracture intervention to enhance fracture complexity in naturally fractured formations particularly shale formations and/or avoid premature sand out.
Setting of the invention
Wells are usually fractured to either make wells economical or to improve the economic value of a well. Injecting fluid, commonly termed fracturing fluid, at a high enough rate and pressure to break down the formation initiates a hydraulic fracture. Continuing to inject the fracturing fluid at the said high rate and pressure propagates the fracture and increases the dimensions of said fracture. This process may be referred to as fracturing the rock by hydraulic means. A proppant-carrying slurry is used to make sure that the fracture is still open and has high permeability after the all fluid has leaked reaching fracture “closure”. It is important to monitor the fracturing treatment to make sure that the treatment is progressing satisfactorily. It is also important to have the ability to monitor a fracturing treatment progress and quickly and accurately determine when intervention may be necessary to either enhance the treatment or to avoid potential problem. For example, recognizing when a fracture crosses a swarm of natural fractures is crucial in making a reliable decision to enhance complexity. This capability may be crucial to fracturing shale formations where far field fracture complexity is highly desired. In other cases, recognizing imminent sand out may be another crucial factor in determining an appropriate strategy.
Applying the right intervention technique is extremely important. This patent describes the a method to recognize and apply such remedial technique